1. Field of the Invention
The present invention relates to a surface discharge AC type plasma display panel (hereinafter, a plasma display panel is referred to simply as a xe2x80x9cPDPxe2x80x9d) and, in particular, to a technology of suppressing error discharge in regions outside of a display region of the PDP.
2. Description of the Background Art
FIG. 9 is a perspective view in section illustrating a structure of a representative surface discharge AC type PDP disclosed in, e.g., Japanese Patent Unexamined Publication No. 11-25866 (1999). In FIG. 9, reference numeral 1 denotes a transparent electrode, numeral 2 denotes a bus electrode of which main component is metal for applying voltage to the transparent electrode 1, numeral 3 denotes a uniform dielectric layer covering the transparent electrode 1 and bus electrode 2, numeral 4 denotes a cathode film that is formed by depositing MgO, and numeral 5 denotes a front glass substrate (i.e., a substrate for a front panel or a substrate body) mounting on its main surface these components 1, 2, 3 and 4.
Numeral 6 denotes an address electrode crossing the bus electrodes 2 at right angles at different levels, numeral 10 denotes a uniform over-glaze layer covering the address electrodes 6, numeral 7 denotes a barrier rib for partitioning lanes of which display pattern is defined by each address electrode 6, numeral 8 denotes a phosphor formed on the wall of the barrier rib 7, and alphabets R, G and B accompanying each numeral 8 denote the color of phosphors of red, green and blue, respectively. Numeral 9 denotes a rear glass substrate (i.e., a substrate for a rear panel, or a substrate body) mounting on its main surface these components 6, 7, 8 and 10. By arranging so that the top of the barrier rib 7 is adjacent to the cathode film 4, there are formed discharge spaces surrounded by the phosphors 8 and cathode film 4, each discharge space being filled with a mixed gas such as of Ne+Xe.
In this construction, a single scanning line is made up of a pair of the transparent electrodes 1 and bus electrodes 2, namely a pair of sustain discharge electrodes (X, Y), as shown in FIG. 9. Therefore, each sustain discharge electrode has a metal electrode part la wherein the bus electrode 2 is mounted on the transparent electrode 1, and a transparent part 1b wherein no bus electrode 2 is mounted thereon.
FIG. 10 is a perspective view in section illustrating a structure of a discharge cell in another surface discharge AC type PDP. In FIG. 10 the same reference numerals 1 to 10 are used as in FIG. 9 for similar parts. In the PDP of FIG. 10, an address electrode 6, an over-glaze layer 10, a pair of sustain discharge electrodes X and Y each of which has no transparent electrode and is made up of a bus electrode 2 alone, a dielectric layer 3, and a cathode film 4 are formed in the order named on the main surface of a rear glass substrate 9. A barrier rib 7 and a phosphor 8 are formed on the main surface of the front glass substrate 5. Each discharge space where the barrier rib 7 and cathode film 4 are in contact for making a lane-like partition is filled with a discharge gas.
In the discharge cell structure of FIG. 9 or FIG. 10, a discharge cell 14 is formed by the point where the lane associated with drive of an arbitrary address electrode 6 defined by two adjacent barrier ribs 7 intersects an arbitrary scanning line defined by a pair of the sustain discharge electrodes (X, Y). By aligning such discharge cell 14 in matrix, a display region 21 of the surface discharge AC type PDP is formed as shown in FIG. 11. Here, in general, the display region in the direction of extension of the sustain discharge electrode X or Y is usually defined as a region sandwiched by core lines of outermost barrier ribs 7a in the alignment of the barrier ribs 7 that partition and define plural lanes associated with plural address electrodes 6 to which ON/OFF signal based on an image data is inputted. However, the outermost barrier ribs 7a are indispensable in defining the display region. Therefore, in the present invention, a display region 21 in the direction of extension of the sustain discharge electrode X or Y is to be defined as a region including the overall width of both outermost barrier ribs 7. Non-display region 22 is defined as a region that contains no outermost barrier ribs 7 and makes contact with the display region 22. As schematically shown in FIG. 12, when the PDP is viewed from front of the front panel, for convenience, the non-display region 22 on the right side is defined as a first non-display region 22A, and the non-display region 22 on the left side is defined as a second non-display region 22B.
Since the outermost barrier ribs 7a have no gas space necessary for occurrence of accidental discharge, which will be later raised as a problem, it is appropriate to interpret based on the non-display region 22 as defined above, even in a known technology to be described later which has been proposed to achieve the object of suppressing accidental discharge within the non-display region 22.
To project a desired image on the display region 21 of the surface discharge AC type PDP shown in FIG. 11, the following system is generally employed. That is, during writing operation, according to the image data, wall charges of different polarities are selectively stored in a portion of a surface 4S of the cathode film 4 to which the sustain discharge electrode pair (X, Y) is projected, the cathode film 4 being above the sustain discharge electrode pair (X, Y), in each discharge cell 14. In the succeeding sustain operation, alternating pulses are applied a predetermined number of times to between the sustain discharge electrode pair X and Y, and sustain discharge is performed a predetermined number of times only by the discharge cell 14 that has stored the wall charges in the previous writing operation. When the sustain operation is completed, the next selective writing operation is then performed through an erasing operation for resetting the wall charges remaining in the discharge cell 14 in which the sustain discharge was performed. The desired image is obtained by repeating a sequence of these selective writing operation, sustain operation and erasing operation.
In the selective writing operation, the applied voltage to the sustain discharge electrode pair X and Y is scanned to select one scanning line at a time, and the voltages corresponding to ON/OFF signals of the image data in the scanning line selected synchronously are outputted to a series of address electrodes 6. On the selected scanning line, in the discharge cell 14 in which a voltage equivalent to ON is applied to the associated address electrode 6, a surface discharge of writing occurs between the sustain discharge electrode pair (X, Y), thereby to store the wall charges necessary for occurrence of sustain discharge in the succeeding sustain operation. On the other hand, even on the selected scanning line, in the discharge cell 14 in which a voltage equivalent to OFF is applied to the associated address electrode 6, no surface discharge of writing occurs and thus no wall discharge is stored. Therefore, this discharge cell 14 becomes an OFF cell causing no sustain discharge in the succeeding sustain operation.
Referring again to FIG. 11, the sustain discharge electrode pairs (X, Y) have a portion extending to the non-display region 22 that is not associated with drive performed by a series of address electrodes 6. Since this portion is in the non-display region, it is desirable that no sustain discharge occurs. At this portion, however, it is impossible to perform the drive control by means of the address electrodes 6, and therefore, during a sequence of the above-mentioned operations, accidental sustain discharge happens to start at the portions of the sustain discharge electrode pair (X, Y) which extend to the non-display region 22. Especially at the time of writing operation, when the ON state voltages based on an image information are applied to address electrodes 6a which the outermost lanes of the display region 21 are associated with, the ON state voltages of the address electrodes 6a exert some influence on the field formation in gas spaces within the non-display regions 22 adjacent to the outermost lanes via one barrier rib 7a. As a result, error writing discharge occurs in each of the non-display regions 22 and it tends to cause error sustain discharge in the succeeding sustain operation.
As a conventional technique of suppressing such accidental sustain discharge caused in the non-display regions 22, there are the followings.
A first technique is one which is disclosed in, e.g., Japanese Patent Unexamined Publication No. 5-114362 (1993). The first prior art discloses a method in which the width of space between the sustain discharge electrode pair (X, Y) constituting one scanning line is set wider at the portion extending to the non-display region. This method utilizes the characteristic that as the width of space between the sustain discharge electrode pair X and Y is increased, the electric field strength between the electrodes X and Y to be formed in the discharge space near an upper part of the space between the electrodes X and Y is weakened thereby to make it difficult to cause sustain discharge therebetween.
A second technique is one which is disclosed in, e.g., Japanese Patent Unexamined Publication No. 8-255574 (1996). The second prior art discloses a method in which dummy address electrodes corresponding to the portions of sustain discharge electrode pairs X and Y which extend to the non-display region are provided respectively, and, during writing operation, voltages equivalent to an OFF level are always applied to the dummy address electrodes, thereby the same outputs as the address electrodes within the display region are also applied to the dummy address electrodes during sustain operation and erasing operation. With this method, the dummy address electrodes can function to control discharge within the non-display region in precisely the same fashion as the address electrodes do within the display region. This results in that discharge in the non-display region is always in OFF state.
However, both methods of the conventional techniques have the following drawbacks.
Drawback I: As a practical matter, it is usually difficult to suppress accidental sustain discharge in the non-display region by means of the method described in Japanese Patent Unexamined Publication No. 5-114362. The reason for this is as follows. In the display region, the strength of electric field that sustain discharge electrode pair forms in a gas space is always suppressed by that the address electrodes maintain a predetermined potential. Whereas in the non-display region, absence of such suppression by the presence of the potential of the address electrodes makes it easy to form a stronger electric field strength between the sustain discharge electrode pair than the display region. Therefore, even if it is tried to suppress accidental discharge by increasing the width of space between the sustain discharge electrode pair, it is usually impossible to obtain a sufficiently wide space in a predetermined alignment pitch of scanning lines.
Drawback II: With the method described in Japanese Patent Unexamined Publication No. 8-255574, the dummy address electrodes maintain a predetermined potential so that the strength of electric field between the sustain discharge electrode pair in the non-display region is suppressed in the same fashion as that in the display region. This enables to suppress sustain discharge in the non-display region under the same condition as in OFF cells in the display region. In this method, however, one or more dummy address electrodes are needed for each of the non-display regions 22A and 22B shown in FIG. 12, in order to drive these dummy address electrodes. The objective can be achieved by bringing the data corresponding to the dummy address electrodes into always OFF during writing operation, with the arrangement that the dummy address electrodes are connected to the output bits of a data driver IC as in the address electrodes for the display region 21 shown in FIG. 12. However, from the point of view of effective display pixel number required for a standard full color PDP, the number of necessary address electrodes is 1920 pieces for VGA, 3072 pieces for XGA, 3840 pieces for SXGA, and 5760 pieces for full-spec HDTV. That is, the output bit number per one general-purpose data IC for PDP can be divided by any one of 64, 96 and 128. It is therefore necessary to increase at least one data IC in order to drive the dummy address electrodes, thus raising the cost. It can be considered to provide exterior electrode terminals corresponding to the dummy address electrodes in addition to the output bits of data IC, in order to avoid the cost increase. Even with this construction, it is however necessary to further provide outputs corresponding to a sequence of erasing operation, writing operation that always corresponds to OFF, and sustain operation, in addition to the outputs of data IC. This case also raises the cost in terms of circuit wiring and signal processing, thus failing to settle the drawback radically.
A first aspect of the invention is directed to a substrate being used for a surface discharge AC type plasma display panel wherein a discharge cell is formed by each intersecting point of each lane and each scanning line, the each lane being partitioned by barrier ribs adjacent to each other within a plurality of barrier ribs provided to extend in a first direction and being associated with drive of an address electrode corresponding to the barrier ribs adjacent to each other within a plurality of address electrodes provided to extend in the first direction, and the each scanning line being defined by an arbitrary sustain discharge electrode pair within a plurality of sustain discharge electrode pairs provided to extend in a second direction orthogonal to the first direction, and a display region defines the discharge cell aligned in matrix, the substrate comprising: a substrate body; the plurality of sustain discharge electrode pairs formed on the substrate body; a dielectric layer formed on the substrate body and covering the plurality of sustain discharge electrode pairs; and a cathode film formed on the dielectric layer, wherein each of the plurality of sustain discharge electrode pairs comprises first and second sustain discharge electrodes opposed to each other at a predetermined spaced interval, and in the first and second non-display regions with respect to the second direction adjacent to the display region, one end of the first sustain discharge electrode is not present within the first non-display region and is present within the display region on the side of a boundary between the display region and the first non-display region.
A second aspect of the invention is directed to the substrate of the first aspect, wherein the other end of the first sustain discharge electrode is present within the second non-display region, one end of the second sustain discharge electrode is not present within the second non-display region and is present within the display region on the side of a boundary between the second non-display region and the display region, and the other end of the second sustain discharge electrode is present within the first non-display region.
A third aspect of the invention is directed to the substrate of the second aspect, wherein the one end of the first sustain discharge electrode is present at a portion of the display region corresponding to one outermost barrier rib defining the boundary between the first non-display region and the display region in the plurality of barrier ribs, and the one end of the second sustain discharge electrode is present at a portion of the display region corresponding to the other outermost barrier rib defining the boundary between the second non-display region and the display region in the plurality of barrier ribs.
A fourth aspect of the invention is directed to the substrate of the second aspect wherein the one end of the first sustain discharge electrode is present at a portion of the display region corresponding to one outermost lane adjacent to the boundary between the first non-display region and the display region in a group of lanes, and the one end of the second sustain discharge electrode is present at a portion of the display region corresponding to the other outermost lane adjacent to the boundary between the second non-display region and the display region in the group of lanes.
A fifth aspect of the invention is directed to the substrate of the third aspect wherein the first sustain discharge electrode comprises a first bus electrode, the second sustain discharge electrode comprises a second bus electrode, one end of the first bus electrode of the first sustain discharge electrode is present at a portion of the display region corresponding to one outermost lane adjacent to the boundary between the first non-display region and the display region, one end of the second bus electrode of the second sustain discharge electrode is present at a portion of the display region corresponding to the other outermost lane adjacent to the boundary between the second non-display region and the display region, the one end of the first bus electrode of the first sustain discharge electrode has a first pattern width greater than a pattern width of portions other than the mentioned one end of the first bus electrode with respect to the first direction, and the one end of the second bus electrode of the second sustain discharge electrode has a second pattern width greater than a pattern width of portions other than the mentioned one end of the second bus electrode with respect to the first direction.
A sixth aspect of the invention is directed to the substrate of the fifth aspect, wherein in the first bus electrode of the first sustain discharge electrode, a pattern width of a portion present in the display region corresponding to the other outermost lane is partially smaller than a pattern width of a portion present in the display region corresponding to a lane adjacent to the other outermost lane, and in the second bus electrode of the second sustain discharge electrode, a pattern width of a portion present in the display region corresponding to the one outermost lane is partially smaller than a pattern width of a portion present in the display region corresponding to a lane adjacent to the one outermost lane.
A seventh aspect of the invention is directed to the substrate of the fifth aspect, further comprising: a plurality of insulating patterns being formed either on the substrate body or in the dielectric layer and extending between adjacent sustain discharge electrode pairs in the second direction, wherein in each of the plurality of insulating patterns, a pattern width in the first direction of a first portion present in the display region corresponding to the one outermost lane and a pattern width in the first direction of a second portion present in the display region corresponding to the other outermost lane are both partially thinner than a pattern width of portions other than the first and second portions of the insulating pattern with respect to the first direction.
An eighth aspect of the invention is directed to a surface discharge AC type plasma display panel comprising: a first panel being the substrate of the first aspect; and a second panel attached at its peripheral part to the first panel.
A ninth aspect of the invention is directed to a surface discharge AC type plasma display device comprising: the surface discharge AC type plasma display panel of the eighth aspect; and a drive unit configured to drive the surface discharge AC type plasma display panel.
A tenth aspect of the invention is directed to a substrate being used for a surface discharge AC type plasma display panel wherein a discharge cell is formed by each intersecting point of each lane and each scanning line, the each lane being partitioned by barrier ribs adjacent to each other within a plurality of barrier ribs provided to extend in a first direction and being associated with drive of an address electrode corresponding to the barrier ribs adjacent to each other within a plurality of address electrodes provided to extend in the first direction, and the each scanning line being defined by an arbitrary sustain discharge electrode pair within a plurality of sustain discharge electrode pairs provided to extend in a second direction orthogonal to the first direction and a display region defines the discharge cell aligned in matrix, the substrate comprising: a substrate body; the plurality of sustain discharge electrode pairs formed on the substrate body; a dielectric layer formed on the substrate body and covering the plurality of sustain discharge electrode pairs; and a cathode film formed on the dielectric layer, wherein each of the plurality of sustain discharge electrode pairs comprises first and second sustain discharge electrodes opposed to each other at a predetermined spaced interval, first and second non-display regions are adjacent to the display region with respect to the second direction, one end of the first sustain discharge electrode is disposed at a portion of the first non-display region which is located in the vicinity of a boundary between the display region and the first non-display region, an extension portion of the first sustain discharge electrode extending in the second direction from the boundary to the one end is smaller in area than a portion of the first sustain discharge electrode at the discharge cell within the display region, and the second sustain discharge electrode extends in the second direction within the first non-display region and is opposed to the extension portion of the first sustain discharge electrode.
An eleventh aspect of the invention is directed to the substrate of the tenth aspect, wherein the extension portion of the first sustain discharge electrode has a length of 200 xcexcm or less in the second direction.
A twelfth aspect of the invention is directed to the substrate of the tenth aspect, wherein a portion of the second sustain discharge electrode which is opposed to the extension portion of the first sustain discharge electrode in the first non-display region comprises a concave portion recessed in the first direction.
A thirteenth aspect of the invention is directed to the substrate of the tenth aspect, wherein one end of the second sustain discharge electrode is disposed at a portion of the second non-display region which is located in the vicinity of a boundary between the display region and the second non-display region, an extension portion of the second sustain discharge electrode extending in the second direction from the boundary between the display region and the second non-display region to the one end of the second sustain discharge electrode is smaller in area than a portion of the second sustain discharge electrode at the discharge cell within the display region, and the first sustain discharge electrode extends in the second direction within the second non-display region and is opposed to the extension portion of the second sustain discharge electrode.
A fourteenth aspect of the invention is directed to a surface discharge AC type plasma display panel comprising: a first panel being the substrate of the tenth aspect; and a second panel attached at its peripheral part to the first panel.
A fifteenth aspect of the invention is directed to a surface discharge AC type plasma display device comprising: the surface discharge AC type plasma display panel of fourteenth aspect; and a drive unit configured to drive the surface discharge AC type plasma display panel.
A sixteenth aspect of the invention is directed to a substrate being used for a surface discharge AC type plasma display panel wherein a discharge cell is formed by each intersecting point of each lane and each scanning line, the each lane being partitioned by barrier ribs adjacent to each other within a plurality of barrier ribs provided to extend in a first direction and being associated with drive of an address electrode corresponding to the barrier ribs adjacent to each other within a plurality of address electrodes provided to extend in the first direction, and the each scanning line being defined by an arbitrary sustain discharge electrode pair within a plurality of sustain discharge electrode pairs provided to extend in a second direction orthogonal to the first direction, and a display region defines the discharge cell aligned in matrix, the substrate comprising; a substrate body; the plurality of sustain discharge electrode pairs formed on the substrate body; a dielectric layer formed on the substrate body and covering the plurality of sustain discharge electrode pairs; and a cathode film formed on the dielectric layer, wherein each of the plurality of sustain discharge electrode pairs comprises first and second sustain discharge electrodes opposed to each other at a predetermined spaced interval, first and second non-display regions are adjacent to the display region with respect to the second direction, a plurality of first discharge spaces extending in the first direction and being aligned in the second direction are disposed in the display region, the first non-display region comprising: a first region adjacent to the display region with respect to the second direction; and a second region adjacent to the first region with respect to the second direction, wherein a plurality of second discharge spaces extending in the first direction and being aligned in the second direction are disposed in the first region, one end of the first sustain discharge electrode is disposed within the first region, the second sustain discharge electrode extends in the second direction within the first region and the second region, a space in each of the plurality of second discharge spaces which is opposed to a portion of the first sustain discharge electrode defining a discharge cell of the respective second discharge spaces is smaller than a space in each of the plurality of first discharge spaces which is opposed to a portion of the first sustain discharge electrode defining the discharge cell of the respective first discharge spaces, and a space in each of the plurality of second discharge spaces which is opposed to a portion of the second sustain discharge electrode defining the discharge cell of the respective second discharge spaces is smaller than a space in each of the plurality of first discharge spaces which is opposed to a portion of the second sustain discharge electrode defining the discharge cell of the respective first discharge spaces.
A seventeenth aspect of the invention is directed to the substrate of the sixteenth aspect, wherein each of the plurality of second discharge spaces is smaller in width in the second direction than each of the plurality of first discharge spaces.
An eighteenth first aspect of the invention is directed to the substrate of the sixteenth aspect, the second non-display region comprising: a first region adjacent to the display region with respect to the second direction; and a second region adjacent to the first region of the second non-display region with respect to the second direction, wherein a plurality of third discharge spaces extending in the first direction and being aligned in the second direction are disposed within the first region of the second non-display region, one end of the second sustain discharge electrode is disposed within the first region of the second non-display region, the first sustain discharge electrode extends in the second direction within the first region and the second region of the second non-display region, a space in each of the plurality of third discharge spaces which is opposed to a portion of the second sustain discharge electrode defining a discharge cell within the respective third discharge spaces is smaller than a space in each of the plurality of first discharge spaces which is opposed to a portion of the second sustain discharge electrode defining the discharge cell within the respective first discharge spaces, and a space in each of the plurality of third discharge spaces which is opposed to a portion of the first sustain discharge electrode defining the discharge cell within the respective third discharge spaces is smaller than a space in each of the plurality of first discharge spaces which is opposed to a portion of the first sustain discharge electrode defining the discharge cell within the respective first discharge spaces.
A nineteenth aspect of the invention is directed to a surface discharge AC type plasma display panel comprising: a first panel being the substrate of the sixteenth aspect; and a second panel attached at its peripheral part to the first panel.
A twentieth aspect of the invention is directed to a surface discharge AC type plasma display device comprising: the surface discharge AC type plasma display panel of the nineteenth aspect; and a drive unit configured to drive the surface discharge AC type plasma display panel.
With the first, eighth or ninth aspect, when the same substrate is used for a PDP, it is able to suppress occurrence of accidental sustain discharge in the first non-display region. This enables to suppress luminous display irregularity in the vicinity of the boundary between the display region and the first non-display region.
With the second, eighth or ninth aspect, when the same substrate is used for a PDP, it is able to suppress occurrence of accidental sustain discharge causing luminous display irregularity in the first and second non-display regions. As a result there is no need for driving the non-display region by dummy address electrodes and for preparing output terminals for driving the dummy address electrodes in addition to a number of data ICs necessary for driving the address electrodes to which image data are outputted. This permits a cost reduction than the conventional techniques using the dummy address electrodes.
With the third, eighth or ninth aspect, when the same substrate is used for a PDP, sustain discharge electrode pairs become uniform patterns in all the lanes within the display region, and luminous property in the outermost lanes can be made substantially the same as that in the lanes located inwardly from the outermost lanes. That is, there is little or no luminous display irregularity in the vicinity of the boundary between the display region and the first and second non-display regions, which can be caused when both of one end of the first and second sustain discharge electrodes are present in the display region.
With the fourth, eighth or ninth aspect, when the same substrate is used for a PDP, luminous display irregularity which occurs in the vicinity of the boundary between the display region and the first or second non-display region, and which can be caused when both of one end of the first and second sustain discharge electrodes are present in the display region, can be made sensorially inconspicuous.
With the fifth, eighth or ninth aspect, when the same substrate is used for a PDP, the surfaces of both the dielectric layer and the cathode film are most greatly swelled at one and the other outermost lanes, and the adjacent barrier ribs to partition the respective outermost lanes are brought into contact with the cathode film away from the greatest swell portions. Thereby, the gap between the barrier rib and cathode film can be reduced to reinforce isolation of discharge between adjacent lanes. In these aspects, the pattern width of one end of the bus electrode is also set to be thicker than other portions. This ensures reliability when probing is performed for the end of the bus electrode in order to check burn-out and short-cut in the process for forming the bus electrode pattern.
With the sixth, seventh, eighth or ninth aspect, when the same substrate is used for a PDP, it is able to further reduce swell of the surface of the dielectric layer in the vicinity of one end of the bus electrode. This permits a further reduction in the gap between the barrier rib and cathode film, thus enabling to more reinforce isolation of discharge between adjacent lanes.
With the tenth to twentieth aspects, when the same substrate is used for a PDP, it is able to weaken the electric field strength which the sustain discharge electrode pair in the non-display region forms in the vicinity of the surface of the cathode film. This enables to suppress occurrence of accidental sustain discharge between sustain discharge electrodes within the non-display region.
It is an object of the present invention to improve quality of display by suppressing occurrence of accidental sustain discharge within the non-display region in a surface discharge AC type PDP, without causing the above-mentioned drawback I (physical limitation) and drawback II (cost increase).